A May 24 special election in a western New York congressional district has turned into a contest with significant national implications.

The 26th Congressional District — which runs from west of Rochester to Buffalo — became vacant earlier this year following the abrupt resignation of scandal-plagued “Craigslist” Rep. Christopher Lee.

A deep-pocketed third-party candidate in the race has created an opportunity for Democrats to pull an upset in a seat the GOP has held for more than 40 years.

That would be a pity, for the GOP has fielded a fine candidate in Assemblywoman Jane Corwin, who also is running on the Conservative and Independence party lines.

The Post endorses Corwin’s candidacy without hesitation.

She has long been a solid supporter of lower taxes and reduced government spending — capstone issues in these fiscally perilous times.

The Democrats selected Erie County Clerk Kathy Hochul, who is also running on the Working Families Party line. Policywise, she’s a carbon copy of former Speaker Nancy Pelosi — and potentially one more automatic vote for more spending and higher taxes.

The wild card is independent Jack Davis, running on the newly created Tea Party line.

The self-funded Davis sounds like a conservative populist — especially on free trade. But he’s more opportunist than anything: He’s run three times for the seat as a Democrat before trying to gain the GOP nomination this year.

Last week, he grew more erratic, abruptly pulling out of a debate and getting into a shoving match with a rival campaign volunteer.

If he weren’t in the race, it would be a Corwin runaway. But he is, and if the Democrat wins, the outcome will be billed as the beginning of a reversal of last fall’s stunning GOP House landslide — emboldening the tax-and-spenders and discouraging responsible government.

A Corwin win, by contrast, would keep up the ongoing revival of the Empire State GOP, which sent more new Republicans to Congress last year than any other state.

New York needs more ideological balance in Washington, DC, and at home.